<%@ page contentType="text/html;charset=UTF-8" language="java"%>
<!DOCTYPE html>
<html>
<head>
<title>登录</title>
</head>
<body>
  <%
      String name = (String) session.getAttribute("attr");
      if (name != null && !name.equals("")) {
          response.sendRedirect("status.jsp");
      }
  %>
  <form action="status.jsp" method="post">
    <input type="text" name="attr" placeholder="请输入...">
    <input type="submit" value="设置">
  </form>
</body>
</html>
